Conventionally, a method of manufacturing a printed matter for preventing forgery or the like is known where a line latent image is printed that is made visible by being superimposed with a line screen filter where line-like stripes are provided on a transparent film (Patent Document 1 and Patent Document 2).
In addition, a method of preventing duplication or the like of electronic image data is known in which a digital watermark is embedded in the electronic image data (Patent Document 3).
Patent Document 1: Japanese Unexamined Patent Publication, First Publication No. 2004-174880
Patent Document 2: Japanese Unexamined Patent Publication, First Publication No. 2001-213042
Patent Document 3: Japanese Unexamined Patent Publication, First Publication No. 2002-64700